1 Introduction
2 Research background and fundamentals
2.1 Research problem
2.2 Motivating example
Approach | Mod. | Exec. | Mon. | UI | Context |
---|---|---|---|---|---|
\(\checkmark \) | ✗ | ✗ | ✗ | ✗ | |
BPMN4CPS [27] | \(\checkmark \) | ✗ | ✗ | ✗ | ✗ |
\(\checkmark \) | ✗ | ✗ | ✗ | ✗ | |
IoT/WS-BPEL [31] | \(\sim \)(BPEL) | \(\checkmark \) | \(\sim \)(BPEL) | ✗ | \(\sim \)(BPEL) |
\(\sim \)(BPEL) | \(\checkmark \) | \(\sim \)(BPEL) | ✗ | \(\sim \)(BPEL) | |
ADiWa[36] | \(\sim \)(conc.) | \(\sim \)(conc.) | ✗ | ✗ | ✗ |
\(\checkmark \) | ✗ | \(\checkmark \)(via GSM) | ✗ | \(\checkmark \) | |
This work | \(\checkmark \) | \(\checkmark \) | \(\sim \)(BPMS) | \(\checkmark \) | \(\checkmark \) |
2.3 Research method
3 Related work
4 Bidirectional architecture for an IoT-aware BPMS
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IoT sensors need to be placed in a process-aware way and be linked to running processes (\(C_1\)).
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Mobile devices should be used, fostering the delivery of work items to the right users (\(C_2\)).
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IoT should support the execution of tasks through context-specific knowledge provisioning (\(C_3\)).
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R1. A BPMS must be aware of current values of IoT objects. (cf. \(C_1\)) Variable attributes, e.g., address and identifiers, must be configurable and traceable, i.e., it must be clear where the data stems from. The acquisition of current values from diverse data variables with standard IoT protocols must be possible. Here, erroneous data must be detected and excluded. Based on an established mapping from IoT variables to process models, IoT data must be sent to a BPMS.
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R2. Each defined variable must be referenceable in the executed process model. (cf. \(C_1\)) Based on current values of certain variable, tasks are triggered or canceled and decisions are made.
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R3. Responsible users must be notified on mobile devices in real time. (cf. \(C_2\)) Process participants must be seamlessly notified when human interaction is required, independent of where the user is located.
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R4. Context-specific knowledge must be provisioned to users. (cf. \(C_3\)) Alongside with activity notification, context-specific and process relevant information must be provisioned to users.
4.1 Connecting current data of IoT objects to BPMS
4.1.1 Variable mapping
4.1.2 Bridging the abstraction gap
Event | \(attr_i^e(v, \ldots , time)\) | \(val_i^e\) | Data type |
---|---|---|---|
1 | (\(RM_1\), \(\ldots \), 2018-01-09 10:15:32) | 300 | Historic |
1 | (QU, \(\ldots \), 2018-01-09 10:15:32) | 211 C | Historic |
1 | (GT, \(\ldots \), 2018-01-09 10:15:32) | 120 | Historic |
2 | (\(RM_1\), \(\ldots \), 2018-01-09 10:15:42) | 133 | Current |
2 | (QU, \(\ldots \), 2018-01-09 10:15:42) | 211 C | Current |
2 | (GT, \(\ldots \), 2018-01-09 10:15:42) | 115 | Current |
4.2 Enrichment of process models with IoT variables
4.2.1 Passive informing
4.2.2 Active interaction
4.3 Establishing the real-time mobile user interface
4.4 Context-specific information provision
5 Architecture and implementation
Topic | Description | Direction |
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/{variable_id}/data | IoT sensor data | IoT to BPMS |
/{actor_id} | Device configuration | BPMS to IoT |
/{actor_id}/tasks | Tasks of specific actor | BPMS to IoT |
/{actor_id}/{variable_id} | Context data for specific user | BPMS to IoT |
/{actor_id}/command | Actors actions (claim, complete, cancel) | IoT to BPMS |
/keepalive | IoT to BPMS |
5.1 IoT data acquisition and BPMS integration
5.2 User interface and IoT object interaction
6 Evaluation and industrial applications
6.1 Application in production industry
6.2 Application for robot human interaction
6.3 Specification of SEMI E10 equipment status via smartwatch
7 Conclusions, implications and future work
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We recognized the advantages that combined IoT and BPM architecture yields compared to traditional information systems for production shop floor. User-specific task coordination based on sensor data as a process oriented solution can provide it seems to be the missing link between production information and operator guidance.
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Modeling IoT-aware business process models is a cumbersome task that requires both deep technical background w.r.t. the IoT-/production system and w.r.t. the used modeling language, e.g., BPMN. To establish a working and accepted solution, an expert in both areas has to tackle this job.
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Understanding BPMN modeled processes by production employees is not as simple as expected. Models have been misinterpreted frequently, and several explanations have been necessary to consolidate a common understanding of the notation and the defined processes.
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As a result, other than planned, BPMN models turned out to be less important as a communication basis for all participating people. Instead, executed IoT-aware processes and concrete task assignments fostered certainty of operators, without knowing the overall flow of work.